Michael Rosen and Laura Wright ask Great British Menu judge Andi Oliver and author of The Flavour Thesaurus Niki Segnit how they describe the flavours of food. Niki describes coriander and lime as "the wooh woohs in 'Sympathy for the Devil' - completely and utterly indispensable". But grapefruit, on the other hand, is "standoffish".. She brings a cheese and a mystery item into the studio for Michael and Laura to taste and then try to put into words. Simile and metaphor, comparision, classification, memory, humour, disgust - all of these help in the tricky but satisfying task of pinning down the unpindownable. Producer Beth O'Dea.